The present invention relates to a tone signal generation apparatus and method which generate one or a plurality of harmony tone signals by pitch-shifting an input tone signal, and more particularly to a technique for reflecting pitch variation, contained in an input tone signal, in a harmony tone signal as desired. The tone signal generation apparatus and method of the present invention is suited for use in a human voice or musical instrument tone processing system belonging to or attached to music-related equipment, such as a karaoke apparatus, an electronic musical instrument, an effector or a personal computer.
Heretofore, there have been known electronic music apparatus and programs which, on the basis of an input tone signal such as a tone signal of a performance tone of a musical instrument or human voice input by a user via a microphone or the like, can automatically generate one or a plurality of harmony tone signals of pitches (i.e., tone pitches) higher or lower by a predetermined pitch interval, such as three and five degrees, than the tone pitch of the input tone signal and can reproduce the thus-generated harmony tone signals together with the input tone signal to thereby simultaneously audibly generate a lead tone (i.e., input tone) and harmony tones (i.e., additional tones). Examples of such electronic music apparatus are disclosed in Japanese Patent No. 2,879,948 (which will hereinafter be referred to as “patent literature 1”) and Japanese Patent Application Laid-open Publication No. HEI-6-202660 (which will hereinafter be hereinafter referred to as “patent literature 2”).
In the conventionally-known apparatus disclosed in patent literature 1 and patent literature 2, a tone pitch corresponding to a fundamental frequency, and hence any one of the pitch names, is identified per predetermined segment (or per predetermined time period) on the basis of frequency (tone pitch) information obtained through frequency analysis of an input tone signal. Then, the input tone signal (more specifically, waveform factor data of one period cut out using a window function corresponding to the identified tone pitch) is subjected to a pitch shift process (i.e., is pitch-shifted) in accordance with predetermined pitch shift amounts determined in accordance with the identified tone pitches of the input tone signal, so that one or a plurality of harmony tone signals of predetermined target tone pitches (each corresponding to any one of musical pitch names) are generated separately as independent additional tones. Further, patent literature 2 discloses that, as a tone generated in response to key depression or key-depressed tone (i.e., input tone signal) is bent up in pitch, i.e. a pitch bend value (also referred to as pitch shift amount) is changed in response to user's operation of a wheel, the electric music apparatus corrects pitch bend amounts of additional tones (corresponding to harmony tone signals) so that the additional tones are set at tone pitches that match up with a chord.
However, each harmony tone signal generated in the conventionally-known apparatus as disclosed in patent literature 1 and patent literature 2 is merely of a tone pitch, determined in in semi tones, which corresponds to any one of the musical pitch names and which is always constant; namely, the generated harmony tone signal does not have minute tone pitch variation less than a semi tone (100 cents). Therefore, a musical expression of each of the generated harmony tone signals would undesirably become mechanical. Particularly, in a case where an input tone signal has tone pitch variation, there can occur a great difference between a rich musical expression of a lead tone (input tone) and a mechanical expression of harmony tones (additional tones), so that a user would easily have an uncomfortable feeling. Therefore, there has been a great demand for an improved electronic music apparatus capable of generating a harmony tone signal reflecting therein minute tone pitch variation contained in an input tone signal, but no such electronic music apparatus has been realized or proposed so far.
Further, in order to generate a harmony tone having mere pitch variation (i.e., pitch variation that does not reflect therein pitch variation of an input tone signal), it is only necessary to perform pitch control on a harmony tone signal of a constant tone pitch, for example, for imparting, for example, a vibrato to the harmony tone signal. Note that, in order to ultimately generate a harmony matching a taste of a user, such as a harmony stable and easy to listen as a whole with pitch variation of its lower-pitched tone smaller than pitch variation of its higher-pitched tone, a harmony clearly presenting a feeling, such as like a major or minor feeling, corresponding to a melody or tune or a harmony with a tense feeling made strong and weak through adjustment of pitch variation of a tension note, there is a need to generate a plurality of harmony tones having different pitch variation. However, for generating a plurality of harmony tones having different pitch variation by use of the conventionally-known technique, it is necessary for a user to make parameter settings for vibrato control etc. for each of the harmony tones to be generated, and such parameter setting operation is extremely cumbersome to the user. Therefore, there has been a great demand for an improved tone signal generation apparatus and method capable of generating one or a plurality of harmony tone signals each reflecting therein pitch variation, contained in an input tone signal, at a desired level, but no such tone signal generation apparatus and method have been realized or proposed so far.